If you want to match colors to touch up your car or paint your bathroom walls, it no longer needs to be a trial-and-error experiment.

Colorgen Ltd., of Woburn, Mass., has developed a personal computer that can analyze almost any color -- from the dingy white of tooth enamel to the feded red of an old Corvette -- and produce a "recipe" for duplicating that shade. The company expects to start production early this year, and founder John O'Brien estimates that it can register sales of $10 million the first year.

Priced at $11,500, the computer is aimed at such small businesses as paint stores and dental practices. Few of them buy the color-matching equipment now available, which costs as much as $100,000, but O'Brien figures they will go for a less expensive computer that can also handle business software. "With this," he says, "we can say, 'Come to the paint store and watch us match Aunt Mamie's dining room walls."

To analyze a color, the computer shines a light on it and identifies the colors that bounce back. Since a false tooth, for example, may look fine in the office under the dentist's fluorescent light and positively ghastly outside in the sun, the computer looks at each color in incandescent, fluorescent, and white light. The machine then checks a data file of the colors the user has available -- all the shades sold in a paint store, for example -- and matches the reflected color with the available ones. It calculates the proper proportions and then tells the user how many parts of which colors to mix.

Then you can paint your house to match your car, your bedroom to match your sheets . . .